This is an old thread, but the first match I found when googling for "greyed out network settings" in vmware fusion.

What worked for me was closing fusion and killing the vmnet-bridge services from the CLI:

sudo killall vmnet-bridge

I had previously removed the "networking" file and the contents of the "vmnet1" and "vmnet8" folders in /Library/Preferences/VMWare Fusion. It didn't make any difference until I killed the vmnet-bridge processes.